Method and arrangement in a communication system

ABSTRACT

Methods and arrangements for generating adjustment commands in a node. The adjustment commands adjust the transmission power of radio signals. The radio signals are sent over at least a first channel and a second channel. The adjustment is performed by adjusting a gain factor. The gain factor is associated with the relation between a first transmission power level of a first channel and a second transmission power level of a second channel.

This application is the U.S. national phase of International ApplicationNo. PCT/SE2007/051005 filed 14 Dec. 2007 which designated the U.S., theentire contents of which is hereby incorporated by reference.

TECHNICAL FIELD

The technology disclosed herein relates to methods and arrangements in acommunication system, in particular to methods and arrangementsgenerating adjustment commands for adjusting the transmission power ofradio signals by adjusting a gain factor.

BACKGROUND

In communication systems based on e.g. Code Divisional Multiple Access(CDMA), outer loop power control is used to meet the desired quality ofservice targets. The outer loop power control may be implemented both inthe user equipment to meet the downlink quality target and also in thebase station to meet the uplink quality target. In wirelesscommunication networks, the downlink is the transmission path from thebase station to the user equipment, and the uplink is the transmissionpath from the user equipment to the base station. It is important thatthe outer loop power control is able to maintain the desired quality ofservice target despite varying radio conditions, which is often the casein wireless communication systems.

The following describes various technical aspects related to inner looppower control, outer loop power control and its convergence in CDMAsystems. In particular the methods and devices described herein relatesto Wideband Code Division Multiple Access (WCDMA) but may be equallyapplicable to other CDMA based technologies such as e.g. cdma 2000because power control, both inner and outer loop, is the hallmark ofCDMA access technology. The methods may also be implemented in aFraction High Speed Downlink Packet Data Access (F-HSDPA).

In CDMA systems the inner loop power control, also called fast powercontrol, runs every time slot, which is typically less than 1 ms (e.g.0.67 ms in WCDMA). In WCDMA the inner loop power control runs in bothuplink and downlink. The fast inner-loop power control adjusts thetransmit power of the sender towards a specific Signal to Interferenceand noise Ratio (SIR) target at the receiver. The aim of the uplink anddownlink inner loop power controls is to counter the effect of fastfading, while maintaining the desired SIR target. In the uplink it alsoensures to compensate for the near-far problem, so that the signalreceived from the users far away in the cell are not swamped out by thestronger signal. During every slot the user equipment estimates the SIRon some known reference or pilot symbols and compares it with some SIRtarget corresponding to the given service (e.g. certain Bit Error Rate(BER) requirements, spreading factor used etc.). In WCDMA, Downlink SIRis measured on Dedicated Physical Control Channel (DPCCH), whichcomprises pilots and Transmitter Power Control (TPC) commands for uplinkpower control. If the estimated SIR is less than the SIR target then theuser equipment generates UP command, otherwise it generates DOWNcommand; in response the base station will increase (in case of UP) ordecrease (in case of DOWN) its downlink transmit power.

The aim of the outer loop power control is to adjust the SIR targetvalue used by the inner loop power control as previously explained,while maintaining a certain link quality. The quality target is theultimate quality target measure, which is set by the network and isexpected from the user equipment to consistently maintain this target toensure the desired quality of service is met throughout the callsession. Due to the varying radio link conditions e.g. user mobility,fast fading etc, the mapping between the SIR target and BER changes overtime. This is a key point as it requires constant adjustment of the SIRtarget to maintain the desired value of BER. This mechanism of adjustingthe SIR target is also referred to as outer loop power control, qualitycontrol or outer loop scheme.

In systems such as enhanced uplink (EUL) version of WCDMA, the outerloop power control is configured to fulfill a quality target based onnumber of transmission attempts i.e.: “after x targeted transmissions,the residual error should be y %”.

The uplink outer loop power control for enhanced uplink channels adjuststhe uplink DPCCH SIR target so the residual error rate after thestipulated maximum number of transmissions is fulfilled.

If the transmission is not successfully decoded after the stipulatedmaximum number of transmissions, the SIR target is increased by e.g. 0.5dB. For every successfully decoded transmission, the corresponding SIRtarget is decreased by a factor inversely proportional to the errorprobability, e.g. about 0.01 dB if the error rate is 2%.

The transmission of data over the air in a wireless communication systemis performed by using a plurality of different physical channels, forexample Dedicated Physical Control CHannel (DPCCH), Dedicated PhysicalData CHannel (DPDCH), Enhanced Dedicated Physical Control CHannel(E-DPCCH) and Enhanced Dedicated Physical Data CHannel (E-DPDCH). Thepower consumptions of these are related to each other by power offsets,i.e. β-values or gain factor relative the power level of the DPCCH.

However, the gain factor used in actual data transmission may beinaccurate, which in turn will affect the overall system performance.Either the reference gain factors obtained through simulations or themethod to calculate other gain factors may result in inaccurate gainfactors. E.g. when the gain factor is lower than required, moretransmission attempts are required to guarantee the successfultransmission. Since current EUL outer loop power control is based ontransmission attempts, this actually means the SIR target is increasedand more power is allocated to DPCCH. However, this is undesired.

The current outer loop power control according to EUL WCDMA increasesthe DPCCH SIR target when the number of transmission attempts is largerthan TA target. This means that all other channels with a power offsetto the DPCCH, such as the E-DPDCH, will also increase their transmitpower.

However, in many cases, the reason for not fulfilling the TA target isdue to too low power on the data channel, E-DPDCH, not due to too lowpower on the control channel DPCCH.

Since the DPCCH is continuously transmitted while E-DPDCH is transmittedmore intermittently, increasing the SIR target and power on the DPCCHcauses unnecessarily high interference.

Moreover, in a situation with bad coverage and high power usage on theuser equipment, DPCCH will “steal” power from the data channel E-DPDCH.

Further on, there is also a problem with the constant power offsets fordifferent transport block size sizes. It is difficult for the network toset the power offset and the enhanced data channel transport formatcombination (E-TFC) to match the TA target exactly. For example if thepower offset is too low to fulfill the TA target, the DPCCH SIR will beincreased until the TA target is fulfilled. Since it may be difficult toknow beforehand what power offset can match the wanted TA target, thiswill most likely lead to an unwanted adjustment of the DPCCH SIR target,and thereby lead to a possibly unwanted interference increase or a toolow DPCCH SIR target.

SUMMARY

The technology disclosed herein aims at obviating or reducing at leastsome of the above mentioned disadvantages associated with existingtechnology.

It is an object of the technology disclosed herein to provide amechanism in a node that decreases the transmission power consumptionand improves the capacity in a wireless communication system.

The object is achieved by a method for generating adjustment commands ina sending node. The adjustment commands adjust the transmission power ofradio signals sent to a receiving node. The radio signals are sent overat least a first channel and a second channel. The adjustment isperformed by adjusting a gain factor. The gain factor is associated withthe relation between a first transmission power level of a first channeland a second transmission power level of a second channel. The methodfurther comprises obtaining a first quality value associated with thefirst channel. Also, the method comprises determining the differencebetween the obtained first quality value and a first quality targetvalue associated with the first channel. Further yet, the methodcomprises adjusting the gain factor based on the determined differencebetween the obtained quality value and the quality target value. Also,the method comprises generating an adjustment command for adjusting thetransmission power of the first channel based on the adjusted gainfactor.

The object is also achieved by a method for generating adjustmentcommands in a receiving node. The adjustment commands adjust thetransmission power of radio signals received from a sending node. Theradio signals are sent over at least a first channel and a secondchannel. The adjustment is performed by adjusting a gain factor. Thegain factor is associated with the relation between a first transmissionpower level of a first channel and a second transmission power level ofa second channel. The first channel and the second channel are used forsending a signal from the sending node to the receiving node. The methodcomprises obtaining a first quality value associated with the firstchannel. Also, the method comprises determining the difference betweenthe obtained first quality value and a first quality target valueassociated with the first channel. Further yet, the method comprisesadjusting the gain factor based on said determined difference betweenthe obtained quality value and the quality target value. Still further,the method comprises generating an adjustment command for adjusting thetransmission power of the first channel based on the adjusted the gainfactor.

The object is also achieved by an arrangement in a sending node forgenerating adjustment commands. The adjustment commands are generatedfor adjusting the transmission power of radio signals sent to areceiving node. The radio signals are sent over at least a first channeland a second channel. The adjustment is performed by adjusting a gainfactor. The gain factor is associated with the relation between a firsttransmission power level of a first channel and a second transmissionpower level of a second channel. The first channel and the secondchannel are used for sending a signal between the sending node and areceiving node. The arrangement comprises an obtaining unit, adapted toobtain a first quality value associated with the first channel. Further,the arrangement comprises a determination unit, adapted to determine thedifference between the obtained first quality value and a first qualitytarget value associated with the first channel. Also, the arrangementcomprises an adjustment unit, adapted to adjust the gain factor based onsaid determined difference between the obtained quality value and thequality target value. Yet further, the arrangement also comprises ageneration unit, adapted to generate an adjustment command for adjustingthe transmission power of the first channel based on the adjusted thegain factor.

The object is also achieved by an arrangement in a receiving node forgenerating adjustment commands. The adjustment commands adjust thetransmission power of radio signals sent from a sending node. The radiosignals are sent over at least a first channel and a second channel. Theadjustment is performed by adjusting a gain factor. The gain factor isassociated with the relation between a first transmission power level ofa first channel and a second transmission power level of a secondchannel. The first channel and second channel are used for sending asignal from the sending node and the receiving node. The arrangementcomprises a first obtaining unit. The first obtaining unit is adapted toobtain a first quality value associated with the first channel. Also,the arrangement comprises a determination unit, adapted to determine thedifference between the obtained first quality value and a first qualitytarget value associated with the first channel. Further, the arrangementcomprises an adjustment unit, adapted to adjust the gain factor based onsaid determined difference between the obtained quality value and thequality target value. Further yet, the arrangement comprises a generatorunit, adapted to generate an adjustment command for adjusting thetransmission power of the first channel based on the adjusted the gainfactor.

Through the present methods and arrangements, the transmit power of anode is utilized in a more efficient way as the quality of the datachannel is guaranteed by itself through the adjustment of gain factorsnot related to the control channel. The situation that poor data channelquality result into SIR target increase, which in turn may result ineven worse data channel as more power may be taken by the controlchannel would be avoided.

Thus an advantage of the present methods and arrangements is that animproved power regulation for radio signals is achieved, which savesenergy resources.

BRIEF DESCRIPTION OF THE DRAWINGS

The technology disclosed herein will now be described more in detail inrelation to the enclosed drawings, in which:

FIG. 1 is a block diagram illustrating embodiments of a wirelesscommunication network.

FIG. 2 is a block diagram illustrating signalling.

FIG. 3 is a flow chart illustrating embodiments of method steps.

FIG. 4 is a flow chart illustrating embodiments of method steps.

FIG. 5 is a block diagram illustrating embodiments of an arrangement ina node.

FIG. 6 is a block diagram illustrating embodiments of an arrangement ina node.

DETAILED DESCRIPTION

The technology disclosed herein is defined as a method and anarrangement which may be put into practice in the embodiments describedbelow.

FIG. 1 depicts a sending node 110 communicating with a receiving node120 within a cell 130 in a wireless communication system 100.

In some embodiments, the sending node 110 may be a user equipment suchas a mobile cellular radiotelephone, a Personal Digital Assistant (PDA),a laptop, a computer or any similar arrangement adapted for radiocommunication. The receiving node 120 may be a base station, a wirelesscommunications station, a fixed station, a control station, a repeateror a similar arrangement for radio communication or any other kind ofdevice capable of communicate radio resources.

However, the situation may as well be the opposite, such as in someother embodiments, wherein the sending node 110 may be a base station, awireless communications station, a fixed station, a control station, arepeater or a similar arrangement for radio communication or any otherkind of device capable of communicate radio resources, and the receivingnode 120 a user equipment such as a mobile cellular radiotelephone, aPersonal Digital Assistant (PDA), a laptop, a computer or any similararrangement for radio communication.

The wireless communication network 100 may also comprise a control node.The control node may be e.g. a Radio Network Controller. The RadioNetwork Controller is a governing element in the wireless communicationnetwork 100, which may be responsible for control of base stations e.g.the receiving node 120, which may be connected to the Radio NetworkController. The Radio Network Controller may carry out radio resourcemanagement, some of the mobility management functions and may be thepoint where encryption is done before user data is sent to and from thesending node 110 and/or the receiving node 120.

The wireless communication system 100 may be based on technologies suchas (for example) Code Division Multiple Access (CDMA), Wideband CodeDivision Multiple Access (WCDMA), and CDMA 2000 etc.

Radio signals are sent from the sending node 110 over a radio link andare received by the receiving node 120. The power of the signal, whichmay be too high or too low to be suitable for communication, isadjustable by the receiving node 120 by e.g. running an inner loop powercontrol, also called fast power control. The inner loop power controlmay run in both on signals sent from the sending node 110 to thereceiving node 120, e.g. as uplink signals or downlink signals. The aimof uplink and downlink inner loop power controls are inter alia tocounter the effect of fast fading, while maintaining a desired SIRtarget. It also ensures to compensate for the near-far problem, so thata signal received from a user far away in the cell is not swamped out bya stronger signal.

The receiving node 120 may estimate a SIR value e.g. on some knownreference signals such as (for example) pilot symbols and compare itwith some SIR target corresponding to a given quality of service target,e.g., certain BLER/BER requirements etc.

In e.g. WCDMA, SIR may be measured on dedicated physical control channel(DPCCH), which DPCCH comprises pilots and TPC commands for uplink powercontrol. If the measured SIR is less than SIR target then the inner looppower control at the receiving node 120 may generate UP command and sendit to the sending node 110, and if the measured SIR is more than SIRtarget then the inner loop power control at the receiving node 120 maygenerate DOWN command and send it to the sending node 110. In response,the sending node 110 will increase, in case of UP command, or decrease,in case of DOWN command, its downlink transmit power.

An outer loop power control is used by the receiving node 120 to meetthe desired quality of service targets. The outer loop power control maybe implemented both in the base station to meet the uplink qualitytarget and in the user equipment to meet the downlink quality target. Itis important that despite varying radio conditions, which is often thecase in wireless communication systems 100, the outer loop is able tomaintain the desired quality of service target.

The outer loop power control may be used to maintain a certain linkquality. The quality target may be set by the network 100 and it isexpected from the sending node 110 to consistently maintain this targetto ensure the desired quality of service is met throughout the callsession. The value of the quality target may depend upon the type ofservice, such as speech, packet data, video data etc, which in turnimpacts the SIR target used for inner loop power control. Thus, anadequate power level for providing the quality target of the radio linkis easily achieved, during normal signal radio signal conditions.

FIG. 2 is a block diagram illustrating signaling between the sendingnode 110 and the receiving node 120 at two different time moments, t=1and t=2, according to some embodiments of the present method. Thesignaling may be made over a plurality of channels, such as a firstchannel 230 and a second channel 240. The first channel 230 may be adata channel, such as (for example) E-DPDCH. The second channel 240 maybe a control channel such as (for example) DPCCH. The adjustment of thetransmission power level of the signals sent over e.g. the first channel230 and the second channel 240 from the sending node 110 to thereceiving node 120 is made by adjusting a gain factor 200. The gainfactor 200 is the difference between the transmit power of the channels230, 240, such as the first channel 230 and the second channel 240.

In the illustrated scenario, the gain factor 200 at t=2 has beenincreased in comparison with the gain factor 200 at t=1. Thus,consequently, the transmit power of the first channel 230 has beenincreased accordingly at the time t=2.

The adjustment of the gain factor 200 may be made by the receiving node120, but it may also be done in the sending node 110.

An advantage of the present method, as illustrated by FIG. 2, is thatthe transmission power of the first channel 230 may be adjusted byadjusting the gain factor 200, without simultaneously adjusting thetransmit power level of the second channel 240.

FIG. 3 is a flowchart illustrating a method in a sending node 110 forgenerating adjustment commands. The adjustment commands are generatedfor a adjusting the transmission power of radio signals sent to areceiving node 120. The radio signals are sent to a receiving node 120over at least a first channel 230 and a second channel 240. The firstchannel 230 may be a data channel, such as (for example) E-DPDCH. Thesecond channel 240 may be a control channel such as (for example) DPCCH.Further, the adjustment is performed by adjusting a gain factor 200. Thegain factor 200 is associated with the relation between a firsttransmission power level of a first channel 230 and a secondtransmission power level of a second channel 240. The signal maycomprise data sent with a certain transport block size. The transportblock size may vary for different data. Also the transport block sizemay influence the gain factor 200 according to some embodiments, suchthat different gain factors 200 may be used for different transportformats.

To appropriately generate an adjustment command for a sending node 110,the method may comprise a number of steps 301-304. It is however to benoted that some of the described method steps are optional and onlycomprised within some embodiments. Further, it is to be noted that themethod steps 301-304 may be performed in any arbitrary chronologicalorder and that some of them, e.g. step 301 and step 303, or even allsteps may be performed simultaneously or in an altered or evencompletely reversed chronological order. The method comprises the stepsof:

Step 301

The sending node 110 obtains a first quality value associated with thefirst channel 230. According to some embodiments, this step is performedby receiving one or more acknowledgement (ACK) or non-acknowledgement(NACK), sent from the receiving node 120, indicating that the signal,previously has been received correctly or erroneously, respectively. Theone or more acknowledgement (ACK) or non-acknowledgement (NACK) mayconcern a plurality of signals representing data or a data block.

The acknowledgement (ACK) and/or non-acknowledgement (NACK) may bereceived from the receiving node 120.

Step 302

Step 302 is optional. According to some embodiments, the sending node110 calculates the number of received acknowledgement (ACK) and/ornon-acknowledgement (NACK) during a certain predetermined time period.The time period may be of arbitrary length, e.g. fractions of a secondor a number of seconds. Thus, according to some embodiments, astatistical survey may be made, counting and summing up the number ofacknowledgements (ACK) and/or non-acknowledgements (NACK) during acertain time period.

Step 303

The sending node 110 determines the difference between the obtainedfirst quality value and a first quality target value associated with thefirst channel 230. According to some embodiments, this step comprisesdetermining the difference between the number of receivedacknowledgements (ACK) and a threshold value. The threshold value mayhave any arbitrary size, such as being one acknowledgement.

According to some embodiments, this step comprises determining thedifference between the number of received non-acknowledgements (NACK)and a threshold value. The threshold value may have any arbitrary size,such as being one non-acknowledgement.

However, according to some embodiments, a statistical survey may havebeen made in the optional step 302. For these embodiments, the thresholdvalue may be expressed in a rate e.g. three receivednon-acknowledgements (NACK) in one second.

Step 304

The sending node 110 adjusts the gain factor 200 based on the determineddifference between the obtained quality value and the quality targetvalue.

According to some embodiments, the gain factor 200 may be decreased ifthe sending node 110 receives an acknowledgement (ACK) from thereceiving node 120, indicating that the previously sent signal, sentfrom the sending node 110 to the receiving node 120, has been correctlyreceived.

According to some embodiments, the gain factor 200 is increased if thesending node 110 receives a non-acknowledgement (NACK) from thereceiving node 120, indicating that a previously sent signal, sent fromthe sending node 110 to the receiving node 120, has been erroneouslyreceived.

According to some embodiments, the gain factor 200 is based on thedetermined difference between the computed number of receivedacknowledgement (ACK) and/or non-acknowledgement (NACK) during a certainpredetermined time period and a threshold limit value. According tothese embodiments, the limit may be set e.g. to three receivednon-acknowledgements (NACK) in one second. If the limit is exceeded, thegain factor 200 may be increased. Thus, according to some embodiments,the sending node 110 may compile the statistics of ACKs and NACKs andthen adjust the gain factor 200 based on N_(nack)/(N_(ack)+N_(nack)),where N_(ack) is the number of transmitted ACKs within a certainmeasurement period, while N_(nack) is the number of transmitted NACKsduring such measurement period.

According to some embodiments, the gain factor 200 (Δβ) may be decreasedwith a step size which is smaller than the step size used when the gainfactor 200 may is increased.

Thus the step size may be set to, as a non-limiting example:

Δβ/3=1, when increasing the gain factor 200, and

${{\Delta\;\beta} = \frac{1}{\left( {1 - {BLERtarget}} \right)}},$when decreasing the gain factor 200, according to some embodiments.

Through some embodiments, the transmission power of the sending node 110is utilized in a more efficient way as the quality of the first channel230, or data channel, is guaranteed by it self through the adjustment ofgain factors 200, which are not directly related to the second channel240, or control channel such as (for example) DPCCH. The situation thatpoor data transmission due to poor first channel 230 quality result intoSIR target increase, which in turn may result in even worse propagationconditions for the first channel 230 as more power may be taken by thesecond channel 240 would be avoided.

FIG. 4 is a flowchart illustrating a method in the receiving node 120for generating adjustment commands. The adjustment commands aregenerated for adjusting the transmission power of radio signals. Theradio signals are received from the sending node 110 over at least thefirst channel 230 and the second channel 240. The adjustment isperformed by adjusting the gain factor 200. The gain factor 200 isassociated with the relation between a first transmission power level ofthe first channel 230 and the second transmission power level of thesecond channel 240. The first channel 230 and second channel 240 areused for sending a signal from the sending node 110 to the receivingnode 120.

The signal may comprise data sent with a certain transport block size.The transport block size may vary for different data. Also the transportblock size may influence the gain factor 200 according to someembodiments.

To appropriately generate an adjustment command for the sending node110, the method may comprise a number of steps 401-408. It is however tobe noted that some of the described method steps are optional and onlycomprised within some embodiments. Further, it is to be noted that themethod steps 401-408 may be performed in any arbitrary chronologicalorder and that some of them, e.g. step 401 and step 406, or even allsteps may be performed simultaneously or in an altered or evencompletely reversed chronological order. The method comprises the stepsof:

Step 401

The receiving node 120 obtains a first quality value associated with thefirst channel 230. The first quality value may be based on any arbitraryerror rate calculation scheme such as (for example) Frame Error Ratio(FER), Block Error Ratio (BLER), Bit Error Ratio (BER) or any othersuitable measure such as outage probability. Thus the quality targetused according to some embodiments may be based on bit, block or frameerror rate, where the bit, block or frame error rate is measured usinge.g. Cyclic Redundancy Check (CRC). However, the quality target may alsoin some embodiments be based on TPC command error and the correspondingdownlink quality may be measured on received TPC commands.

The step of obtaining a quality value of the first channel 230 may insome embodiments be performed by making an estimation of the qualityvalue of the first channel 230. It may also according to someembodiments be performed by receiving a quality value of the firstchannel 230 from another node.

According to some embodiments, the receiving node 120 may measure theblock error rate using N_(err)/(N_(corr)+N_(err)), where N_(corr) is thenumber of correctly received transport block within a certainmeasurement period, and N_(err) is the number of erroneously receivedtransport block in such measurement period.

Step 402

The receiving node 120 determines the difference between the obtainedfirst quality value and a first quality target value associated with thefirst channel 230.

Such difference may be determined by comparing the obtained firstquality value of the first channel 230 with a quality target value ofthe first channel 230. The quality target value of the first channel 230may according to some embodiments have different values for differentservices. The value of the quality target value may depend upon the typeof service, which in turn impacts the SIR target used for inner looppower control, as explained above. As a non limiting example, 1% BLERtarget may be used for speech, 10% BLER target may be used for packetdata, 0.1 BLER % may be used for video telephony and so on.

Step 403

In the optional step 403, the receiving node 120 establish, according tosome embodiments, the number of transmission attempts the sending node110 has made to send a signal to the receiving node 120. The optionalstep of obtaining a number of transmission attempts of the second signalover the first channel 230 may be performed by counting the number oftransmission attempts, according to some embodiments. The number oftransmission attempts may also according to some embodiments be receivedfrom another node comprised within the wireless communication network100.

Step 404

Step 404 is optional. According to some embodiments, the number oftransmission attempts may be compared with a transmission attemptsthreshold value. The transmission attempts threshold value may accordingto some embodiments have different values for data blocks of differenttransport block size.

The transmission attempts threshold value may according to someembodiments have different values for different services.

Step 405

In the optional step 405, the receiving node 120 computes, according tosome embodiments, if the signal sent over the first channel 230 from thesending node 110 is correctly received. The correctness of the signalmay be estimated by an arbitrary data correctness algorithm such as e.g.CRC.

Step 406

Step 406 is optional. The receiving node 120 obtains, according to someembodiments, a second quality value associated with the second channel240. According to some embodiments, the second quality value associatedwith the second channel 240 may be a SIR value. According to someembodiments, the SIR value may be estimated by the receiving node 120.

Step 407

Step 407 is optional. The receiving node 120 detects, according to someembodiments, a difference between the obtained second quality value anda quality target value associated with the second channel. According tosome embodiments, the second quality value may be a SIR value and thequality target value may be a SIR target value.

Step 408

The receiving node 120 adjusts the gain factor 200 based on saiddetermined difference between the obtained quality value and the qualitytarget value.

According to some embodiments, the gain factor 200 may be decreased by acertain step if e.g. the second quality value, such as e.g. a SIR value,exceeds a threshold, such as e.g. a SIR target value, and if the signalcomprising transport blocks of data is correctly received within theallowed number of transmission attempts, the gain factor 200 may bedecreased by a certain step size. According to some embodiments, thestep size may be 1/(1−BLER). Otherwise, the gain factor 200 may beincreased. According to some embodiments, the gain factor 200 may beincreased by the step size 1.

According to some embodiments, the gain factor 200 (Δβ) may be decreasedwith a step size which is smaller than the step size used when the gainfactor 200 may is increased.

Thus the step size may be set to, as a non-limiting example:

Δβ=1, when increasing the gain factor 200, and

${{\Delta\;\beta} = \frac{1}{\left( {1 - {BLERtarget}} \right)}},$when decreasing the gain factor 200, in accordance with someembodiments.

Through some embodiments, the transmission power of the sending node 110is utilized in a more efficient way as the quality of the first channel230, or data channel, is guaranteed by it self through the adjustment ofgain factors 200, which are not directly related to the second channel240, or control channel such as e.g. DPCCH. The situation that poor datatransmission due to poor first channel 230 quality result into SIRtarget increase, which in turn may result in even worse propagationconditions for the first channel 230 as more power may be taken by thesecond channel 240 may thus be avoided.

FIG. 5 is a block diagram illustrating embodiments of an arrangement 500in a sending node 110. To perform the method steps 301-304 in thesending node 110, for generating adjustment commands for adjusting thetransmission power of radio signals sent over a radio link to areceiving node 120, the sending node 110 comprises an arrangement 500 asdepicted in FIG. 5.

The sending node arrangement 500 is adapted to generate adjustmentcommands for adjusting the transmission power of radio signals. Theradio signals are sent to a receiving node 120 over at least a firstchannel 230 and a second channel 240. The radio signals may comprisedata in transport blocks of different sizes. Further, the adjustment isperformed by adjusting a gain factor 200. The gain factor 200 isassociated with the relation between a first transmission power level ofa first channel 230 and a second transmission power level of a secondchannel 240. The first channel 230 and second channel 240 are used forsending a signal between the sending node 110 and a receiving node 120.

The sending node arrangement 500 comprises an obtaining unit 501,adapted to obtain a first quality value associated with the firstchannel 230.

According to some embodiments, the sending node arrangement 500 maycomprise a calculator unit 502. The optional calculator unit 502 may beadapted to calculate the number of received acknowledgement (ACK) and/ornon-acknowledgement (NACK) during a certain time period. The time periodmay be predetermined.

Further, the sending node arrangement 500 comprises a determination unit503. The determination unit 503 is adapted to determine the differencebetween the obtained first quality value and a first quality targetvalue associated with the first channel 230.

The sending node arrangement 500 also comprises an adjustment unit 504.The adjustment unit 504 is adapted to adjust the gain factor 200 basedon said determined difference between the obtained quality value and thequality target value.

The sending node arrangement 500 may also, according to someembodiments, comprise a processor unit 506. The processor unit 506 isadapted to process data, perform computations and communicate with otherunits comprised within the sending node arrangement 500.

Any, some or all of the units 501, 502, 503, 504 and/or 506 may becomprised within the same physical unit or units, according to someembodiments. Thus the units 501, 502, 503, 504 and/or 506 are to be seenrather as entities providing a certain specified function, not withnecessity comprised within separate physical units.

FIG. 6 is a block diagram illustrating embodiments of an arrangement 600in a receiving node 120. To perform the method steps 401-408 in thereceiving node 120, for generating adjustment commands for adjusting thetransmission power of radio signals sent over a radio link from asending node 110, the receiving node 110 comprises an arrangement 600 asdepicted in FIG. 6.

The arrangement 600 is situated in a receiving node 120. The receivingnode arrangement 600 is adapted to generate adjustment commands, foradjusting the transmission power of radio signals. The radio signals aresent from a sending node 110 over at least a first channel 230 and asecond channel 240. The adjustment of the transmission power isperformed by adjusting a gain factor 200. The gain factor 200 isassociated with the relation between a first transmission power level ofa first channel 230 and a second transmission power level of a secondchannel 240. The first channel 230 and the second channel 240 are usedfor sending signals from the sending node 110 to the receiving node 120.

The receiving node arrangement 600 comprises a first obtaining unit 601,adapted to obtain a first quality value associated with the firstchannel 230.

Further, the receiving node arrangement 600 comprises a determinationunit 602, adapted to determine the difference between the obtained firstquality value and a first quality target value associated with the firstchannel 230.

Also, according to some embodiments, the receiving node arrangement 600may comprise a third obtaining unit 603. The third obtaining unit 603may further be adapted to obtain the number of transmission attempts thesending node 110 has made to send a signal to the receiving node 120.

Also, according to some embodiments, the receiving node arrangement 600may comprise a comparison unit 604, adapted to compare the obtainednumber of transmission attempts with a transmission attempts thresholdvalue.

According to some embodiments, the receiving node arrangement 600comprises a computation unit 605, adapted to compute if the data sentover the first channel 230 from the sending node 110 is correctlyreceived.

According to some embodiments, the receiving node arrangement 600 alsocomprises a second obtaining unit 606, adapted to obtain a secondquality value associated with the second channel 240.

The receiving node arrangement 600 comprises, according to someembodiments, a detection unit 607. The optional detection unit 607 maybe adapted to detect a difference between the obtained second qualityvalue and a quality target value associated with the second channel 240.

Also, the receiving node arrangement 600 comprises an adjustment unit608, adapted to adjust the gain factor 200 based on said determineddifference between the obtained quality value and the quality targetvalue.

Also, according to some optional embodiments, the receiving nodearrangement 600 comprises a sending unit 609, adapted to emit a signalto another node.

Any, some or all of the units 601, 602, 603, 604, 605, 606, 607, 608and/or 609 may be comprised within the same physical unit or units,according to some embodiments. Thus the units 601, 602, 603, 604, 605,606, 607, 608 and/or 609 are to be seen rather as entities providing acertain specified function, not with necessity comprised within separatephysical units.

The present methods and arrangements may with particular advantage beused for technologies such as an Enhanced Uplink (EUL) or High-SpeedUplink Packet Access (HSUPA) in the wireless communication system 100,as the present methods and arrangements implements a fast and accuratemechanism to adjust the transmission power levels on a plurality ofchannels 230, 240, by adjusting the gain factor 200.

The description of the embodied methods and arrangements has focusedmainly and by means of example only, on the uplink power control in thereceiving node 120. The present methods and arrangements may howeveralso be performed e.g. partly in the base station controller or radionetwork controller (RNC), for example when the sending node 110 is insoft handover.

Further by means of example and in order to simplify the comprehension,the term SIR has been consistently used in this text when describing aSignal to noise and Interference Ratio, which is the ratio between thelevel of a desired signal to the level of background noise and signaldisturbance. The higher the ratio, the less obtrusive is the backgroundnoise. However, there exist other acronyms which are sometimes used todescribe the same or a similar ratio, like e.g. the Signal to NoiseRatio (SNR or S/N), Signal to Noise and Interference Ratio (SNIR),Carrier to interference Ratio (CIR), Signal to Interference and NoiseRatio (SINR) or an inversion of the ratio, like Interference to SignalRatio, (ISR). Any of these or similar ratios may be used in the contextof this description instead of the SIR.

The methods for adjusting the transmission power of radio signals sentover a first channel 230 and a second channel 240 from a sending node110 according to some embodiments may be implemented through one or moreprocessors, such as the processor 506 in the sending node arrangement500, depicted in FIG. 5; or the processor 608 in the receiving nodearrangement 600 depicted in FIG. 6, together with computer program codefor performing the functions of the methods. The program code mentionedabove may also be provided as a computer program product, for instancein the form of a data carrier carrying computer program code forperforming the method according to the technology disclosed herein whenbeing loaded into the sending node 110 and/or the receiving node 120.The data carrier may be a CD ROM disc, a memory stick, or any othermedium such as a disk or tape that can hold machine readable data. Thecomputer program code may furthermore be provided as pure program codeon a server and downloaded to the sending node 110 and/or the receivingnode 120 remotely.

While the methods and arrangements described in this document aresusceptible to various modifications and alternative forms, specificembodiments thereof are shown by way of example in the drawings and areherein described in detail. It should be understood, however, that thereis no intent to limit the present methods and arrangements to theparticular forms disclosed, but on the contrary, the methods andarrangements are to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the methods andarrangements as defined by the claims.

Like reference numbers signify like elements throughout the descriptionof the figures.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless expressly stated otherwise. Itshould be further understood that the terms “comprises” and/or“comprising” when used in this specification is taken to specify thepresence of stated features, integers, steps, operations, elements,and/or components, but does not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. It will be understood that when anelement is referred to as being “connected” or “coupled” to anotherelement, it can be directly connected or coupled to the other element orintervening elements may be present.

Furthermore, “connected” or “coupled” as used herein may includewirelessly connected or coupled. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

Unless otherwise defined, all terms including technical and scientificterms used herein have the same meaning as commonly understood by one ofordinary skill in the art to which these methods and arrangementsbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand will not be interpreted in an idealized or overly formal senseunless expressly so defined herein.

For purposes of illustration, embodiments of the present methods andarrangements are described herein in the context of a user equipment anda base station. It will be understood, however, that the present methodsand arrangements are not limited to such embodiments and may be embodiedgenerally as any electronic device that includes radio signalpropagation means thereon.

The invention claimed is:
 1. A method in a sending node for generatingadjustment commands, for adjusting the transmission power of radiosignals sent to a receiving node over at least a data channel and acontrol channel, the adjustment is performed by adjusting a gain factor,which gain factor is associated with the relation between a firsttransmission power level of the data channel and a second transmissionpower level of the control channel, the method comprising: obtaining afirst quality value associated with the data channel, by receiving oneor more acknowledgement (ACK) or non-acknowledgement (NACK), sent fromthe receiving node, indicating that the signal, previously has beenreceived correctly or erroneously, respectively, obtaining a secondquality value associated with the control channel; determining a firstdifference between the obtained first quality value and a first qualitytarget value associated with the data channel, determining a seconddifference between the obtained second quality value and a secondquality target value associated with the control channel, adjusting thegain factor based on the first difference and the second difference. 2.The method according to claim 1, wherein the gain factor is decreased ifthe sending node receives an acknowledgement (ACK) from the receivingnode, indicating that the previously sent signal, sent from the sendingnode to the receiving node, has been correctly received.
 3. The methodaccording to claim 1, wherein the gain factor is increased if thesending node receives a non-acknowledgement (NACK) from the receivingnode, indicating that a previously sent signal, sent from the sendingnode to the receiving node, has been erroneously received.
 4. The methodaccording to claim 1, comprising the further step of: calculating thenumber of received acknowledgement (ACK) and/or non-acknowledgement(NACK) during a certain predetermined time period, and wherein the stepof adjusting the gain factor is based on the determined differencebetween the computed number of received acknowledgement (ACK) and/ornon-acknowledgement (NACK) during a certain predetermined time periodand a threshold limit value.
 5. The method according to claim 1, whereinthe first quality target value is set to different value levels fordifferent services.
 6. The method according to claim 1, wherein the gainfactor is adjusted in dependence of the transport block size.
 7. Themethod according to claim 1, wherein the gain factor is adjusted onlyfor transport blocks of the previously used transport block size.
 8. Themethod according to claim 1, wherein the sending node is represented bya base station.
 9. The method according to claim 1, wherein the sendingnode is represented by a user equipment.
 10. An arrangement in a sendingnode for generating adjustment commands, for adjusting the transmissionpower of radio signals sent to a receiving node over at least a datachannel and a control channel, the adjustment is performed by adjustinga gain factor, which gain factor is associated with the relation betweena first transmission power level of the data channel and a secondtransmission power level of the control channel, which data channel andcontrol channel are used for sending a signal between the sending nodeand a receiving node, the arrangement comprises: an obtaining unit,adapted to obtain: (1) a first quality value associated with the datachannel, by receiving one or more acknowledgement (ACK) ornon-acknowledgement (NACK), sent from the receiving node, indicatingthat the signal, previously has been received correctly or erroneously,respectively, and (2) a second value associated with the controlchannel; a determination unit, adapted to determine: (a) a firstdifference between the obtained first quality value and a first qualitytarget value associated with the data channel, and (b) a seconddifference between the obtained second quality value and a secondquality target value associated with the control channel; and anadjustment unit, adapted to adjust the gain factor based on the firstdifference and the second.
 11. The arrangement according to claim 10,further comprising: a calculator unit, adapted to calculate the numberof received acknowledgement (ACK) and/or non-acknowledgement (NACK)during a certain predetermined time period.